Cage for bearing

ABSTRACT

A bearing cage includes a first circular ring; a second circular ring provided to be spaced apart from the first ring in a coaxial relationship with the first ring; a plurality of pillars provided in a circumferential direction of the first ring and the second ring, one end of the pillar being connected to the first ring and the other end of the pillar being connected to the second ring; a plurality of pockets provided in the circumferential direction and configured to provide a space in which a bearing roller is accommodated, the pocket being formed to be surrounded by the first ring, the pillars and the second ring; and first reservoirs provided in the pillars and comprising a first storage space for storing lubricant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No. PCT/KR2018/010372 filed on Sep. 5, 2018, the entire contents of which are herein incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a bearing cage.

BACKGROUND

A bearing is a mechanical element which serves to position a shaft of a rotating machine at a certain position and to rotate the shaft while supporting the weight of the shaft and the load applied on the shaft. When the bearing is used while being mounted to the shaft, it is necessary to reduce the frictional force between the bearing and the shaft in order to facilitate the rotation of the shaft. To do this, lubricant such as oil, grease, or the like is supplied to the bearing.

FIG. 1 is a schematic cross-sectional view of a Dual Clutch Transmission (DCT) when viewed in an axial direction. Bearings are coupled to shafts A, B, C and D of the DCT and lubricant is stored in a certain space inside the DCT. The stored lubricant may be supplied to bearings, which are coupled to the shafts A and B located at a height to which the lubricant does not reach, by churning. The shaft A corresponds to an input shaft, the shafts B and C correspond to an output shaft, and the shaft D corresponds to a differential shaft (differential gear shaft). The term “churning” refers to an operation in which elements, which are coupled to the lower shafts C and D located at a height to which the lubricant reaches, splash the lubricant upward while rotating.

During the operation of the DCT, the lubricant may also be supplied to bearings coupled to the upper shafts A and B by the churning. However, when the operation of the DCT is resumed after being left in a non-use state for a long time, the lubricant adhered to the bearings coupled to the upper shafts A and B may be completely dried. If the DCT is operated in a state in which the lubricant is completely dried (i.e., dry start), the upper shafts A and B may rotate with no lubricant, and the frictional force between the shafts and the bearings may be increased, which may cause damage to the bearings and/or the shafts.

SUMMARY

One object of the present disclosure is to provide a bearing cage that enables a bearing coupled to a mechanical device to operate with lubricant even if the mechanical device is operated again after being left in a non-use state for a long time.

In one embodiment, a bearing cage comprises: a first circular ring; a second circular ring provided to be spaced apart from the first ring in a coaxial relationship with the first ring; a plurality of pillars provided in a circumferential direction of the first ring and the second ring, one end of the pillar being connected to the first ring and the other end of the pillar being connected to the second ring; a plurality of pockets provided in the circumferential direction and configured to provide a space in which a bearing roller is accommodated, the pocket being formed to be surrounded by the first ring, the pillars and the second ring; and first reservoirs provided in the pillars and comprising a first storage space for storing lubricant.

In another embodiment, a bearing cage comprises: a first circular ring; a second circular ring provided to be spaced apart from the first ring in a coaxial relationship with the first ring; a plurality of pillars provided in a circumferential direction of the first ring and the second ring, one end of the pillar being connected to the first ring and the other end of the pillar being connected to the second ring; a plurality of pockets provided in the circumferential direction and configured to provide a space in which a bearing roller is accommodated, the pocket being formed to be surrounded by the first ring, the pillars and the second; and second reservoirs having a second storage space to be opened in a radially outward direction for storing lubricant, the second reservoir being formed to extend in a radially inward direction from an inner surface of the pillar, which is a surface facing inward of the first ring of the second ring, out of the surfaces of the pillar. The second reservoir is formed to be surrounded by: a pair of (2-1)th wall portions formed to extend in the radially inward direction from the inner surface of the pillar and provided to be spaced apart with each other in the circumferential direction; a (2-2)th wall portion configured to connect radially inner ends of the (2-1)th wall portions; and a (2-3)th wall portion formed to extend in the radially outward direction from an end of the (2-2)th wall portion in a direction opposite to a first direction, which extends from the second ring toward the first ring, so as to block at least a portion of an opening formed between the (2-1)th wall portions.

According to the present disclosure, lubricant that has been used during an operation of a mechanical device can be stored in a first storage space of a first reservoir provided in the bearing cage, and the lubricant can be supplied to bearing rollers even when the mechanical device is resumed after the operation is stopped for a long time.

Further, according to the present disclosure, since the bearing case comprises a first reservoir having a first storage space opened in a radially inward direction and a second reservoir having a second storage space opened in a radially outward direction, when a bearing is coupled to a mechanical device in a state that a shaft direction of the bearing is horizontal to the ground, lubricant can be stored in the first storage space of the first reservoir below the shaft and the lubricant can be stored in the second storage space of the second reservoir above the shaft. Accordingly, a sufficient amount of lubricant can be supplied to bearing rollers even when the mechanical device is reoperated after the operation is stopped for a long time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of a Dual Clutch Transmission (DCT) when viewed in an axial direction.

FIG. 2 is a perspective view of a bearing cage according to a first embodiment of the present disclosure.

FIG. 3 is a longitudinal cross-sectional view showing a state in which rollers and an inner ring of a bearing are coupled to the bearing cage according to the first embodiment of the present disclosure.

FIG. 4 is a perspective view specifically showing a first reservoir according to the first embodiment of the present disclosure.

FIG. 5A is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the first reverser according to the first embodiment of the present disclosure.

FIG. 5B is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the first reverser according to the first embodiment of the present disclosure.

FIG. 5C is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the first reverser according to the first embodiment of the present disclosure.

FIG. 6 is a longitudinal cross-sectional view showing a state in which rollers and an inner ring of a bearing are coupled to a bearing cage according to a second embodiment of the present disclosure.

FIG. 7 is a perspective view specifically illustrating a second reservoir according to the second embodiment of the present disclosure.

FIG. 8A is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the second reservoir according to the second embodiment of the present disclosure.

FIG. 8B is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the second reservoir according to the second embodiment of the present disclosure.

FIG. 8C is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the second reservoir according to the second embodiment of the present disclosure.

FIG. 9 is a longitudinal cross-sectional view showing a state in which rollers and an inner ring of a bearing are coupled to a bearing cage according to a third embodiment of the present disclosure.

FIG. 10 is a perspective view specifically showing a first reservoir and a second reservoir according to the third embodiment of the present disclosure.

FIG. 11A is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the first reservoir and the second reservoir according to the third embodiment of the present disclosure.

FIG. 11B is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the first reservoir and the second reservoir according to the third embodiment of the present disclosure.

FIG. 11C is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the first reservoir and the second reservoir according to the third embodiment of the present disclosure.

FIG. 12A is a longitudinal cross-sectional view schematically showing a process of assembling the inner ring in the bearing cage according to the third embodiment of the present disclosure.

FIG. 12B is a longitudinal cross-sectional view schematically showing a process of assembling the inner ring in the bearing cage according to the third embodiment of the present disclosure.

FIG. 12C is a longitudinal cross-sectional view schematically showing a process of assembling the inner ring in the bearing cage according to the third embodiment of the present disclosure.

FIG. 12D is a longitudinal cross-sectional view schematically showing a process of assembling the inner ring in the bearing cage according to the third embodiment of the present disclosure.

FIG. 13 is a plan view showing a state in which the roller of the bearing is accommodated in the bearing cage according to the third embodiment of the present disclosure.

FIG. 14 is a plan view showing a state in which the roller, the inner ring and an outer ring of the bearing are assembled to the bearing cage according to the third embodiment of the present disclosure.

FIG. 15 is a perspective view specifically illustrating a pillar according to a fourth embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, some embodiments of the present disclosure will be described in detail through exemplary drawings. It should be noted that, in adding reference numerals to components in the drawings, the same components are made to have the same symbols as possible even if they are illustrated on the other drawings. In addition, if it is determined that detailed descriptions on related known configurations or functions in describing the embodiments of the present disclosure prevent understanding of the embodiments of the present disclosure, detailed descriptions thereof will be omitted.

First Embodiment

FIG. 2 is a perspective view of a bearing cage according to a first embodiment of the present disclosure. FIG. 3 is a longitudinal cross-sectional view showing a state in which rollers and an inner ring of a bearing are coupled to the bearing cage according to the first embodiment of the present disclosure. FIG. 4 is a perspective view specifically showing a first reservoir according to the first embodiment of the present disclosure. The bearing cage according to the first embodiment of the present disclosure will be described below with reference to FIGS. 2 to 4.

Referring to FIGS. 2 and 3, the bearing cage according to the first embodiment of the present disclosure comprises a first ring 1, a second ring 2, pillars 3, pockets 4 and first reservoirs 10.

The second ring 2 is arranged coaxially with the first ring 1, and is provided spaced apart from the first ring 1. A diameter of the second ring 2 may be smaller than that of the first ring 1. In this case, the bearing cage may be used for a tapered roller bearing.

Hereinafter, a direction extending from the second ring 2 toward the first ring 1 will be referred to as a first direction. In addition, a direction extending from a central axis of the first ring 1 and the second ring 2 toward the first ring 1 and the second ring 2 will be referred to as a radially outward direction, and a direction extending from the first ring 1 and the second ring 2 toward the central axis of the first ring 1 and the second ring 2 will be referred to as a radially inward direction (see FIG. 3).

The pillar 3 is configured such that one end thereof is connected to the first ring 1 and the other end thereof is connected to the second ring 2. A plurality of pillars 3 are provided in a spaced-apart relationship with each other along a circumferential direction of the first ring 1 and the second ring 2. The plurality of pillars 3 may be provided to be spaced at equal intervals.

The first ring 1, the second ring 2 and a pair of pillars 3 form a pocket 4. That is, the pocket 4 is formed to be surrounded by the first ring 1, the pillars 3 and the second ring 2, and a plurality of pockets 4 are provided along the circumferential direction. The pocket 4 provides a space in which a roller of the bearing is accommodated. The pillar 3 may function as a partition between one pocket 4 and another pocket 4 adjacent thereto, and may serve to prevent rollers accommodated in adjacent pockets 4 from coming into contact with each other.

The first reservoir 10 is provided in the pillar 3, and has a first storage space 11 for storing lubricant. When the operation of a mechanical device to which the bearing is coupled is stopped, the used lubricant may be stored in the first storage space 11. When the mechanical device is reoperated, the lubricant stored in the first storage space 11 may be supplied to the roller by virtue of a centrifugal force caused by the rotation of a shaft.

That is, when the operation of the mechanical device is resumed in a state in which the mechanical device is left in a non-use state for a long time, the lubricant adhered to the rollers and the bearing cage may be completely dried, and consequently the rotation of the shaft may begin with no lubricant (i.e., dry start). In this case, the frictional force between the rollers and the shaft is increased, which may cause damage to the bearing and the shaft.

In particular, in the case of the tapered roller bearing in which the diameter of the second ring 2 is smaller than the diameter of the first ring 1, the used lubricant may flow downward along inclined surfaces of the pillars 3. In the bearing cage of the present disclosure, the used lubricant may be stored in the first reservoir 10, which prevents the mechanical device from operating with no lubricant.

Hereinafter, the first reservoir 10 will be described in more detail with reference to FIG. 4. The first storage space 11 may be provided on an inner surface 3 a, which faces inward of the first ring 1 or the second ring 2, out of surfaces of the pillar 3. The first storage space 11 may be formed to be open in the radially inward direction.

For example, the first storage space 11 may be formed to be recessed in the radially outward direction from the inner surface 3 a. Alternatively, the first storage space 11 may be formed to be surrounded by wall portions extending in the radially inward direction from the inner surface 3 a. That is, the first reservoir 10 may further comprise: a pair of (1-1)th wall portions 13 formed to extend in the radially inward direction and provided to be spaced apart from each other along the circumferential direction; and a (1-2)th wall portion 15 formed to extend in the radially inward direction from the inner surface 3 a and configured to connect the (1-1)th wall portions 13. The (1-1)th wall portions 13 and the (1-2)th wall portion 15 may form the first storage space 11 therein. Alternatively, the first storage space 11 formed by the (1-1)th wall portions 13 and the (1-2)th wall portion 15 may be formed to be further recessed in the radially outward direction.

In this case, as illustrated in FIG. 4, one ends of the (1-1)th wall portions 13 may be coupled to the second ring 2, and the (1-2)th wall portion 15 may connect the other ends (the first direction ends) of the (1-1)th wall portions 13. Alternatively, when the (1-1)th wall portions 13 are not coupled to the second ring 2, the (1-2)th wall portion 15 may be provided both at end portions in the first direction and at end portions in the opposite direction to the first direction.

Further, even in the case where the diameter of the second ring 2 is set to be smaller than the diameter of the first ring 1, the (1-2)th wall portion 15 may be provided so as to connect the first direction ends of the (1-1)th wall portions 13. That is, in the case where the diameter of the second ring 2 is set to be smaller than the diameter of the first ring 1, the pillar 3 is formed to be inclined in the radially outward direction as it goes from the second ring 2 toward the first ring 1. Thus, even if the (1-2)th wall portion 15 is formed only at the first direction end, the first storage space 11 may be formed by the inclination of the pillar 3.

In the meantime, the bearing cage according to the first embodiment of the present disclosure may be formed of a plastic material. In this case, the bearing cage may generally be manufactured by injection-molding. FIG. 5 is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the first reservoir according to the first embodiment of the present disclosure.

Since, the first storage space 11 is provided to be recessed in the radially outward direction relative to the (1-2)th wall portion 15, when separating a mold 70 which has been inserted to form the first storage space 11 from the bearing case, the mold 70 may not be separated because it is locked to the (1-2)th wall portion 15.

To address this, the (1-2)th wall portion 15 may comprise a (1-2)th inclined surface 16 formed to extend from the bottom surface of the first storage space 11 and configured to gradually increase a thickness in the radially inward direction as it goes in the first direction. The (1-2)th inclined surface 16 is an inclined surface formed to extend from the bottom surface of the first storage space 11 and configured to be moved in the radially inward direction as it goes in the first direction.

Further, the (1-1)th wall portion 13 may comprise a (1-1)th inclined surface 13 a. The (1-1)th inclined surface 13 a may be formed to extend from a position spaced apart from the (1-2)th wall portion 15 by a certain distance in a direction opposite to the first direction (see FIG. 4). The (1-1) the inclined surface 13 a may be formed such that a thickness in the radially inward direction is increased as it goes in the first direction (see FIG. 4). That is, the (1-1)th inclined surface 13 a is an inclined surface configured to be moved in the radially inward direction as it goes in the first direction.

The inserted mold 70 may press the (1-1)th inclined surface 13 a and the (1-2)th inclined surface 16 when being separated from the bearing cage, so that the first reservoir 10 is elastically deformed in the radially outward direction and thus the inserted mold 70 can be easily separated from the bearing cage (see FIG. 5B).

In this case, the bearing cage may further comprise a first displacement space 19 to form a space in which the first reservoir 10 is elastically displaced in radially outward direction. The first displacement space 19 may be formed at the rear side of the first reservoir 10 in the direction opposite to the first direction between the (1-2)th wall portion 15 and the inner surface 3 a of the pillar 3. When the mold 70 is separated from the bearing cage, the (1-1)th wall portions 13 and the (1-2)th wall portion 15 may be elastically displaced to the first displacement space 19 so that the mold 70 can be easily separated. As described above, since the bearing cage according to the first embodiment of the present disclosure comprises the (1-1)th inclined surface 13 a, the (1-2)th inclined surface 16, the first displacement space 19, or the like, the bearing cage according to the first embodiment of the present disclosure can be produced in a simplified manner through a conventional mold.

Second Embodiment

FIG. 6 is a longitudinal cross-sectional view showing a state in which rollers and an inner ring of a bearing are coupled to a bearing cage according to a second embodiment of the present disclosure. FIG. 7 is a perspective view specifically illustrating a second reservoir according to the second embodiment of the present disclosure. The bearing cage according to the second embodiment of the present disclosure will be described with reference to FIGS. 6 and 7. The bearing cage according to the second embodiment of the present disclosure is different from the bearing cage according to the first embodiment in that the second reservoir is provided instead of the first reservoir.

The bearing cage according to the second embodiment of the present disclosure comprises a second reservoir 20 formed to extend in the radially inward direction from the pillar 3. The second reservoir 20 may comprise a second storage space 21 formed to be open in the radially outward direction for storing lubricant.

As illustrated in FIG. 6, in a case in which the bearing is coupled to the mechanical device such that the axial direction of the bearing is arranged to be horizontal to the ground, when the operation of the mechanical device is stopped, the lubricant may be stored in the second storage space 21 located above the shaft, and when the operation of the mechanical device is resumed, the lubricant stored in the second storage space 21 may be supplied to the roller by virtue of a centrifugal force caused by the rotation of the shaft. Thus, even if the operation of the mechanical device is resumed after the mechanical device is left in a non-use state for a long time, it possible to prevent the mechanical device from operating with no lubricant by the lubricant stored in the second reservoir 20.

Referring to FIG. 7, the second reservoir 20 may further comprise: (2-1)th wall portions 23; a (2-2)th wall portion 25; and a (2-3)th wall portion 27. The second storage space 21 may be formed to be surrounded by the (2-1)th wall portions 23, the (2-2)th wall portion 25 and the (2-3)th wall portion 27. The second reservoir 20 may further comprise a (2-4)th wall portion 28, and the second storage space 21 may be further surrounded by the (2-4)th wall portion 28.

First, a pair of (2-1)th wall portions 23 may be formed to extend in the radially inward direction from the inner surface 3 a of the pillar 3 while being spaced apart from each other along the circumferential direction. Further, the (2-1)th wall portions 23 may comprise a first extended portion 23 a formed to extend in the radially inward direction from an end of the inner surface 3 a in the direction opposite to the first direction; and a second extended portion 23 b formed to extend in the first direction from a radially inward end of the first extended portion 23 a. That is, the (2-1)th wall portions 23 may be formed in an L shape.

Next, the (2-2)th wall portion 25 may connect the radially inward ends of the (2-1)th wall portions 23 with each other. The (2-3)th wall portion 27 may extend in the radially outward direction from an end of the (2-2)th wall portion 25 in the direction opposite to the first direction so as to block at least a portion of an opening formed between the (2-1)th wall portions 23.

The (2-4)th wall portion 28 may extend in the radially outward direction from a first direction end of the (2-2)th wall portion 25 so as to block at least a portion of an opening formed between the (2-1)th wall portions 23. The (2-4)th wall portion 28 may be formed lower than the (2-1)th wall portions 23 with reference to the (2-2)th wall portion 25. That is, both the (2-4)th wall portion 28 and the (2-1)th wall portions 23 extend in the radially outward direction from the (2-2)th wall portion 25, but the radially outward end of the (2-4)th wall portion 28 is positioned adjacent to the (2-2)th wall portion 25 relative to the radially outward end of the (2-1)th wall portion 23.

An opening 29 is formed in the (2-4)th wall portion 28, so that the lubricant stored in the second storage space 21 can be easily discharged to the roller 7 (see FIG. 7).

In the meantime, the bearing cage according to the second embodiment of the present disclosure may also be formed of a plastic material. In this case, the bearing cage may generally be manufactured through a mold. FIG. 8 is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the second reservoir according to the second embodiment of the present disclosure.

Since the second storage space 21 is provided to be recessed more radially inwardly than the (2-4)th wall portion 28, when the mold 70 inserted to form the second storage space 21 is separated from the bearing cage, the mold 70 may not be separated because it is locked to the (2-4)th wall portion 28.

To address this, the (2-4)th wall portion 28 may comprise a (2-4)th inclined surface 281. The (2-4)th inclined surface 281 may be formed to extend from the bottom surface of the second storage space 21. Further, The (2-4)th inclined surface 281 may be formed to gradually increase a thickness in the radially outward direction as it goes in the first direction. That is, the (2-4)th inclined surface 281 is a inclined surface configured to be moved in the radially outward direction as it goes in the first direction.

When the inserted mold 70 is separated from the bearing cage, the mold 70 may press the (2-4)th inclined surface 281 so that the second reservoir 20 is elastically deformed in the radially inward direction and thus the mold 70 can be easily separated from the bearing cage (see FIG. 8B). As described above, since the bearing cage according to the second embodiment of the present disclosure comprises the (2-4)th inclined surface 281, the bearing cage according to the second embodiment of the present disclosure can be produced in a simplified manner through a conventional mold.

Third Embodiment

FIG. 9 is a longitudinal cross-sectional view showing a state in which rollers and an inner ring for a bearing are coupled to a bearing cage according to a third embodiment of the present disclosure. FIG. 10 is a perspective view specifically showing a first reservoir and a second reservoir according to the third embodiment of the present disclosure. The bearing cage according to the third embodiment of the present disclosure will be described below with reference to FIGS. 9 and 10.

As illustrated in FIGS. 9 and 10, the bearing cage according to the third embodiment of the present disclosure may comprise both the first reservoir 10 of the first embodiment and the second reservoir 20 of the second embodiment. In this case, the (2-1)th wall portion 23 may be formed to extend in the radially inward direction from the (1-1)th wall portion 13.

In the present embodiment, the bearing cage comprises both the first reservoir 10 provided with the first storage space 11 opened in the radially inward direction and the second reservoir 20 provided with the second storage space 21 opened in the radially outward direction. Thus, in a case in which the bearing is coupled to the mechanical device such that the axial direction of the bearing is horizontal to the ground, the lubricant may be stored in the first storage space 11 of the first reservoir 10 below the shaft and may be stored in the second storage space 21 of the second reservoir 20 above the shaft, as illustrated in FIG. 9. Therefore, even if the operation of the mechanical device is resumed after the mechanical device is left in a non-use state for a long time, a sufficient amount of lubricant may be supplied to the roller 7 for the bearing.

FIG. 11 is a longitudinal cross-sectional view schematically illustrating a process of injection-molding the first reservoir and the second reservoir according to the third embodiment of the present disclosure. The first reservoir 10 according to the third embodiment of the present disclosure may also comprise the (1-1)th inclined surfaces 13 a, the (1-2)th inclined surfaces 16 and the first displacement space 19. The second reservoir 20 according to the third embodiment of the present disclosure may also comprise the (2-4)th inclined surfaces 281. Accordingly, when the mold 70 is separated from the bearing cage, the first reservoir 10 may be elastically displaced in the radially outward direction, and the second reservoir 20 may be elastically displaced in the radially inward direction. As a result, the mold 70 can be easily separated from the bearing cage (see FIG. 11B).

FIG. 12 is a longitudinal cross-sectional view schematically showing a process of assembling the inner ring in the bearing cage according to the third embodiment of the present disclosure. FIG. 13 is a plan view showing a state in which the roller for the bearing is accommodated in the bearing cage according to the third embodiment of the present disclosure. FIG. 14 is a plan view showing a state in which the roller, the inner ring and an outer ring of the bearing are assembled to the bearing cage according to the third embodiment of the present disclosure. A process of assembling the inner ring and the outer ring in the bearing cage according to the third embodiment of the present disclosure will be described below with reference to FIGS. 12 to 14. Hereinafter, descriptions will be mainly made on the bearing cage according to the third embodiment of the present disclosure, however configurations to be described below may be similarly applied to the bearing cage according to the first embodiment or the second embodiment of the present disclosure.

First, a bearing cage where rollers 7 are accommodated into a pocket and an inner ring 5 to be assembled to the bearing cage are prepared, as illustrated in FIG. 12A. Then, as illustrated in FIGS. 12A to 12C, the inner ring 5 of the bearing may be assembled inside the first ring 1 and the second ring 2 in a second direction extending from the first ring 1 toward the second ring 2. More specifically, FIG. 12B shows a state in which a lower flange 5 b of the inner ring 5 is in contact with the (2-2)th wall portion 25 in the process of assembling the inner ring 5 in the bearing cage, and FIG. 12C shows a state in which the inner ring 5 is coupled to the bearing cage.

As illustrated in FIGS. 13 and 14, the (2-1)th wall portions 23 may be provided so as to extend in the radially inward direction from the inner surface of the pillar such that the (2-2)th wall portion 25 protrudes more radially inwardly than the second ring 2. Further, as illustrated in FIG. 13, the (2-1)th wall portions (23) may be provided so as to extend in the radially inward direction from the inner surface such that the (2-2)th wall portion 25 protrudes more radially inwardly than the roller 7 when the roller 7 is accommodated in the pocket (24). Thus, as illustrated in FIG. 12B, when the inner ring 5 is assembled to the bearing cage, the lower flange 5 b of the inner ring 5 may not be brought into contact with the roller 7 and may be brought into contact with the (2-2)th wall portion 25. When the inner ring 5 continues to move in the second direction after the inner ring 5 is in contact with the (2-2)th wall portion 25, the inner ring 5 may press the (2-2)th wall portion 25 to elastically deform the (2-2)th wall portion 25 in the radially outward direction, and then may be completely assembled to the bearing cage as illustrated in FIG. 12C.

In this case, the first ring 1 and the second ring 2 may formed of a material such as plastic to be elastically deformable. The (2-2)th wall portion 25 may be configured to be inclined in the radially outward direction along the direction extending from the first ring 1 toward the second ring 2, so that the (2-2)th wall portion 25 can be easily pressed in the radially outward direction by the inner ring 5 being assembled.

As described above, in the course of assembling the inner ring 5 to the bearing cage, the inner ring 5 is coupled to the bearing cage in the state in which the lower flange 5 b of the inner ring 5 presses the (2-2)th wall portions 23 without coming into contact with the roller 7. This makes it possible to prevent the roller 7 from being damaged by the inner ring 5 in the course of assembling the inner ring 5 to the bearing cage.

After the inner ring 5 is assembled to the bearing cage as illustrated in FIG. 12C, the outer ring is assembled as illustrated in FIGS. 12D and 14. Although, the outer ring is not illustrated in FIGS. 12D and 14, FIG. 12D shows a state in which the outer ring is coupled to the bearing cage in the direction extending from the second ring toward the first ring. In FIG. 14, a symbol “o” denotes a raceway formed by an inner peripheral surface of the outer ring.

In this case, the pocket may have a size to form a clearance s between the pocket and the roller 7 as illustrated in FIG. 14, so that the roller accommodated in the pocket can be displaced in the radially inward direction by the assembly of the outer ring. That is, when the outer ring is coupled to the bearing cage, the roller 7 is pressed in the radially inward direction. After the assembling of the outer ring is completed, the roller 7 protrudes more radially inwardly than the (2-2)th wall portion 25, so that a raceway i in which the roller 7 and the inner ring are in contact with each other may be formed at the radially inward position more than the (2-2)th wall portion 25.

Fourth Embodiment

FIG. 15 is a perspective view specifically illustrating a pillar according to a fourth embodiment of the present disclosure. A bearing cage according to the fourth embodiment of the present disclosure differs from the bearing cages according to the first to third embodiments in that the bearing cage according to the fourth embodiment further comprise a third reservoir 30 and/or a fourth reservoir 40, and the configuration of the pillar 3 of the bearing cage according to the fourth embodiment is different from those of the first to third embodiments

Referring to FIG. 15, the bearing cage according to the fourth embodiment of the present disclosure may further comprise the third reservoir 30. The third reservoir 30 may be provided in the pillar 3 to be spaced apart in the first direction from the first reservoir 10. The third reservoir 30 may be provided with a third storage space 31 as a space for storing lubricant. The third storage space 31 may be formed to be recessed in the radially outward direction from the inner surface 3 a or may be formed to be surrounded by (3-1)th wall portions 33 and (3-2)th wall portion 35. The (3-2)th wall portion 35 may also comprise a (3-2)th inclined surface 33 a formed to extend from the bottom surface of the third storage space 31 and configured to be moved in the radially inward direction as it goes in the first direction. The (3-2)th inclined surface 33 a may perform a function similar to the (1-2)th inclined surface 16 shown in FIG. 5. Further, the third reservoir 30 may comprise a third displacement space 39 in which the third reservoir 30 can be elastically displaced in the radially outward direction. The third displacement space 39 may perform a function similar to the first displacement space 19 shown in FIG. 5. The third reservoir 30 has a substantially same configuration with the first reservoir 10, and thus detailed descriptions thereof will be omitted.

Since the bearing cage according to the fourth embodiment of the present disclosure further comprises the third reservoir 30, in a case in which the bearing is coupled to the mechanical device such that the axial direction of the bearing is horizontal to the ground, when the operation of the mechanical device is stopped, the lubricant may be stored in the third storage space 31 located below the shaft. Further, even if the operation of the mechanical device is resumed after the mechanical device is left in a non-use state for a long time, the mechanical device can be operated in a state where a sufficient amount of lubricant is supplied to the roller.

Further, the bearing cage according to the fourth embodiment of the present disclosure may further comprise a fourth reservoir 40 provided with a fourth storage space 41. The fourth storage space 41 may be formed to be recessed in the radially outward direction on a surface, which faces the center of the first ring 1, out of surfaces of the first ring 1. In addition, the fourth reservoir 40 may comprise a fourth inclined surface 43 formed to extend from the bottom surface of the fourth storage space 41 and configured to gradually increase a thickness in the radially inward direction as it goes in the first direction. That is, the fourth inclined surface 43 is an inclined surface configured to be moved in the radially inward direction as it goes in the first direction. Lubricant may also be stored in the fourth storage space 41. Further, the fourth inclined surface 43 may be pressed when the mold is separated from the bearing cage.

In addition, the pillar 3 of the bearing cage according to the fourth embodiment of the present disclosure may comprise a pair of chamfered portions 50. The chamfered portions 50 may be provided on both sides of the inner surface 3 a of the pillar 3 in the circumferential direction, and may face the roller accommodated in the pocket 4. Hereinafter, the chamfered portions 50 will be explained with reference to the bearing cage according to the fourth embodiment. However, the chamfered portions 50 may be provided similarly even in the bearing cages according to the first to third embodiments.

The chamfered portion 50 may comprise a contact portion 51 and a non-contact portion 53. The contact portion 51 refers to a portion which is formed to protrude toward the roller to be in direct contact with the roller, and the non-contact portion 53 refers to a portion which is formed to be recessed more inward than the contact portion 51 and is not in contact with the roller. Since the chamfered portion 50 has the non-contact portion 53 which is not in contact with the roller, it is possible to reduce the frictional force generated between the roller and the chamfered portion 50.

In this case, the contact portion 51 may be arranged close to the second ring 2, and the non-contact portion 53 may be arranged close to the first ring 1. Further, a guide surface may be formed as a step portion between the contact portion 51 and the non-contact portion 53 at a boundary between the contact portion 51 and the non-contact portion 53.

Further, in a case where the roller is accommodated in the pocket 4 shown in FIG. 15, a space defined by the non-contact portion 53, the guide surface and the roller may function as a passage through which the lubricant accommodated in each storage space moves. That is, since the chamfered portion 50 has the contact portion 51 and the non-contact portion 53, even if the bearing cage has a complicated structure comprising the first reservoir 10, the second reservoir 20 and the third reservoir 30, the lubricant stored in the first storage space 11, the second storage space 21 and the third storage space 31 may smoothly flow out to the space defined by the non-contact portion 53, the guide surface and the roller. Thus, even in the case in which a large amount of lubricant is accommodated in each reservoir, the lubricant can be smoothly discharged to the outside, which makes it possible to prevent agitate resistance from being increased during the drive of the bearing.

Further, the guide surface may be formed to be inclined from the second ring 2 toward the first ring 1 as it goes in the radially outward direction. Thus, the guide surface can guide the supply path of the lubricant to be supplied to the roller. That is, it is possible to guide the lubricant in a desired direction by adjusting the inclination angle of the guide surface.

Although the above embodiments of the present disclosure are exemplified for the purpose of describing the technical spirit of the present disclosure, it should be noted that various modification and variations can be devised by those skilled in the art to which the present disclosure pertains without departing from the technical spirit and scope of the present disclosure. Accordingly, the embodiments described herein are merely examples for describing the technical sprit of the present disclosure, and the technical sprit of the present disclosure is not limited to the embodiments. Further, the scope of the present disclosure should be construed within the appended claims, and all technical ideas falling within the equivalent scope thereof should be interpreted as being included in the scope of the disclosure. 

What is claimed is:
 1. A bearing cage, comprising: a first ring; a second ring provided to be spaced apart from the first ring in a coaxial relationship with the first ring; a plurality of pillars provided in a circumferential direction of the first ring and the second ring, one end of the pillar being connected to the first ring and the other end of the pillar being connected to the second ring; a plurality of pockets provided in the circumferential direction and configured to provide a space in which a bearing roller is accommodated, the pocket being formed to be surrounded by the first ring, the pillars and the second ring; and first reservoirs provided in the pillars and comprising a first storage space for storing lubricant.
 2. The bearing cage of claim 1, wherein the first storage space is provided on an inner surface, which faces inward of the first ring or the second ring, out of surfaces of the pillar, and is configured to be formed to be open in a radially inward direction.
 3. The bearing cage of claim 2, wherein the first storage space is formed to be recessed in a radially outward direction from the inner surface.
 4. The bearing cage of claim 2, wherein the first reservoir further comprises: a pair of (1-1)th wall portions formed to extend in the radially inward direction from the inner surface and provided to be spaced apart from each other along the circumferential direction; and a (1-2)th wall portion formed to extend in the radially inward direction from the inner surface and configured to connect the pair of (1-1)th wall portions to each other, wherein the first storage space is formed to be surrounded by the pair of (1-1)th wall portions and the (1-2)th wall portion.
 5. The bearing cage of claim 4, wherein a diameter of the second ring is smaller than that of the first ring, the pillar is formed to be inclined in a radially outward direction as it goes in a first direction extending from the second ring toward the first ring, and the (1-2)th wall portion is provided to connect first direction ends of the (1-1)th wall portions to each other.
 6. The bearing cage of claim 5, wherein the (1-1)th wall portion comprises a (1-1)th inclined surface formed to extend from a position spaced apart from the (1-2)th wall portion by a certain distance in a direction opposite to the first direction and configured such that a thickness in the radially inward direction is increased as it goes in the first direction.
 7. The bearing cage of claim 5, wherein the (1-2)th wall portion comprises a (1-2)th inclined surface formed to extend from a bottom surface of the first storage space and configured such that a thickness in the radially inward direction is increased as it goes in the first direction.
 8. The bearing cage of claim 5, further comprising: a first displacement to form a space in which the first reservoir is elastically displaced, wherein the first displacement space is formed at the rear side of the first reservoir in a direction opposite to the first direction between the (1-2)th wall portion and the inner surface of the pillar.
 9. The bearing cage of claim 1, further comprising: second reservoirs formed to extend in a radially inward direction from the pillars and having a second storage space formed to be opened in a radially outward direction to store the lubricant.
 10. The bearing cage of claim 9, wherein the second reservoir comprises: a pair of (2-1)th wall portions formed to extend in the radially inward direction from an inner surface, which faces inward of the first ring or the second ring, out of surfaces of the pillars, and provided to be spaced apart with each other in the circumferential direction; a (2-2)th wall portion provided to connect radially inner ends of the pair of (2-1)th wall portions to each other; and a (2-3)th wall portion formed to extend in the radially outward direction from an end of the (2-2)th wall portion in a direction opposite to the first direction so as to block at least a portion of an opening formed between the (2-1)th wall portions. wherein the second storage space is formed to be surrounded by the pair of (2-1)th wall portions, the (2-2)th wall portion and the (2-3)th wall portion.
 11. The bearing cage of claim 10, wherein the second reservoir further comprises a (2-4)th wall portion formed to extend in the radially outward direction from a first direction end of the (2-2)th wall portion, so as to block the at least a portion of the opening formed between the (2-1)th wall portions, wherein the second storage space is further surrounded by the (2-4)th wall portion.
 12. The bearing cage of claim 11, wherein the (2-4)th wall portion comprises a (2-4)th inclined surface formed to extend in the first direction from a bottom surface of the second storage space and configured to gradually increase a thickness in the radially outward direction as it goes in the first direction.
 13. The bearing cage of claim 11, wherein the (2-4)th wall portion is formed lower than the (2-1)th wall portions with reference to the (2-2)th wall portion.
 14. The bearing cage of claim 10, wherein the pair of (2-1)th wall portion is provided to extend in the radially inward direction from the inner surface such that the (2-2)th wall portion protrudes more radially inwardly than the roller when the roller is accommodated in the pocket.
 15. The bearing cage of claim 14, wherein the first ring and the second ring are configured to be elastically deformed in the radially outward direction, a diameter of the second ring is smaller than that of the first ring, and when an inner ring for a bearing is assembled into the first ring and the second ring in the direction extending from the first ring toward the second ring after the rollers are accommodated in the pillars, the inner ring presses the (2-2)th wall portion without coming into contact with the roller to elastically deform at least the (2-2)th wall portion in the radially outward direction.
 16. The bearing cage of claim 15, wherein the (2-2)th wall portion is provided to be inclined in the radially outward direction along the direction extending from the second ring toward the first ring.
 17. The bearing cage of claim 1, further comprising: third reservoirs provided in the pillars to be spaced apart from the first reservoir in a direction extending from the second ring toward the first ring, and having a third storage space for storing the lubricant.
 18. The bearing cage of claim 1, wherein the pillar comprises a pair of chamfered portions provided on both circumferential sides of the inner surface, which faces inward of the first ring or the second ring, out of surfaces of the pillar, and provided to face the roller, and wherein the chamfered portion has a contact portion formed to protrude toward the roller and in contact with the roller; and a non-contact portion which is not in contact with the roller.
 19. A bearing cage, comprising: a first ring; a second ring provided to be spaced apart from the first ring in a coaxial relationship with the first ring; a plurality of pillars provided in a circumferential direction of the first ring and the second ring, one end of the pillar being connected to the first ring and the other end of the pillar being connected to the second ring; a plurality of pockets provided in the circumferential direction and configured to provide a space in which a bearing roller is accommodated, the pocket being formed to be surrounded by the first ring, the plurality of pillars and the second; and second reservoirs formed to extend in a radially inward direction from the pillars and having a second storage space to be opened in a radially outward direction to store lubricant.
 20. The bearing cage of claim 19, wherein the second reservoir is provided to protrude in the radially inward direction from an inner surface, which faces inward of the first ring or the second ring, out of surfaces of the pillar, and wherein the second storage space is formed to be surrounded by: a pair of (2-1)th wall portions formed to extend in the radially inward direction from the inner surface and provided to be spaced apart with each other in the circumferential direction; a (2-2)th wall portion configured to connect radially inner ends of the (2-1)th wall portions; and a (2-3)th wall portion formed to extend in the radially outward direction from an end of the (2-2)th wall portion in a direction opposite to a first direction, which extends from the second ring toward the first ring, so as to block at least a portion of an opening formed between the (2-1)th wall portions. 